The present invention relates in general to spirit duplicating and more particularly concerns a novel spirit duplicating ink that may be used in making duplicating masters for use with conventional spirit duplicating machines to legibly reproduce many copies of the master while the master is essentially free from smudge.
A conventional spirit duplicating machine carries a master that has been impressed with methyl violet through typing or printing that is released upon copy paper moistened with a volatile spirit fluid to reproduce the master image on the copy paper. A master is typically capable of producing at least about 200 copies.
A serious problem with conventional duplicating masters is their tendency to smudge. The problem is especially serious in connection with providing duplicating masters in book form for use by schools to reproduce student learning material from the masters upon a conventional duplicating machine. The present approach for dealing with this problem involves interleaving duplicating masters with protective sheets to prevent smudging while the book is being handled. Furthermore, care must be taken during assembly of books of duplicating masters to avoid smudging the masters. Both the protective interleaved sheets and the special handling required during binding increase the cost of spirit duplicator master books.
Not only is the smudge problem disadvantageous from the standpoint of interfering with the clarity of reproduction from masters, but the smudge problem also results in secretarial or other personnel handling masters subject to hands and/or wearing apparel dirtied by the easily transferable ink on the master.
Accordingly, it is an important object of the invention to provide improved materials and techniques for significantly reducing the smudge problem noted above.
It is another object of the invention to achieve the preceding object while still providing many legible copies from the master.
It is another object of the invention to achieve one or more of the preceding objects with an improved ink for spirit duplicator masters that is so free from smudging that it does not dirty the hands of secretarial or other personnel during normal handling and may be applied to masters bound in books without protective sheets interleaved between adjacent masters. It is another object of the invention to achieve one or more of the preceding objects with an improved spirit duplicating ink that may be used with conventional printing presses to reproduce spirit duplicating masters essentially free of the smudge problem noted above.